He finished 19th in voting for the 1971 AL MVP for playing in 141 Games and having 491 At Bats, 81 Runs, 156 Hits, 23 Doubles, 4 Triples, 11 Home Runs, 75 RBI, 15 Stolen Bases, 87 Walks, .318 Batting Average (which was third best in the American League to Bobby Murcer of the New York Yankees [.331], and Tony Oliva of the Minnesota Twins [.337]), .422 On-base percentage, .448 Slugging Percentage, 220 Total Bases, 4 Sacrifice Hits, 3 Sacrifice Flies and 2 Intentional Walks.

After his major league career, Rettenmund served as hitting coach for the Texas Rangers (1983–85), the Athletics (1989–90), the Padres (1991–99), the Atlanta Braves (2000–01), and the Detroit Tigers (2002).

After three years out of the majors, Rettenmund returned as hitting coach of the Padres in June, 2006, replacing Dave Magadan. However, he himself was replaced in mid-season the next year (July 31, 2007), by Wally Joyner[1]